1. Field of the Invention
The present invention relates to a film deposition apparatus, a film deposition method and a storage medium that deposit a reaction product on a surface of a substrate in a layer-by layer manner by supplying process gases that react to each other and perform a plasma process onto the substrate.
2. Description of the Related Art
An ALD (Atomic Layer Deposition) method that deposits a reaction product of plural kinds of process gases (i.e., reaction gases) that react to each other in a layer-by-layer manner on a surface of a substrate such as a semiconductor wafer (which is called a “wafer” hereinafter) by supplying the plural kinds of process gases in turn is taken as one of film deposition methods of depositing a thin film such as a silicon oxide film (SiO2) and the like on the substrate. As a film deposition apparatus that performs a film deposition process by using the ALD method, for example, as disclosed in Japanese Patent Application Laid-Open Publication No. 2010-239102, an apparatus is known that allows plural wafers to be arranged on a turntable provided in a vacuum chamber and, for example, supplies respective process gases in order onto these wafers by rotating the turntable relative to plural gas supplying part arranged facing the turntable.
In the meanwhile, a wafer heating temperature (i.e., a film deposition temperature) in the ALD method is low, for example, about 300° C., compared to an ordinary CVD (Chemical Vapor Deposition) method. Because of this, if one of the process gases is, for example, an NH3 (ammonia) gas and the like, this NH3 gas may not be activated to the extent that a reaction product can be generated. Moreover, for example, an organic substance contained in the process gases may be taken into a thin film as impurities. Accordingly, as disclosed in Japanese Patent Application Laid-Open Publication No. 2011-40574, a technology is known that performs a plasma process with a film deposition of a thin film to activate the process gas or to reduce the impurities from the thin film.
At this time, if an interconnection structure is formed inside a wafer, there is a concern that the plasma gives electric damage to the interconnection structure. On the other hand, if a plasma source is away from the wafer to reduce the plasma damage to the wafer, because an activated species such as ions and radicals in the plasma readily become inactivated under a pressure condition of performing the film deposition process, there is a concern that it becomes difficult for the activated species to reach the wafer and a sufficient plasma process may not be implemented.
Furthermore, for example, if a depressed portion of a reverse tapered shape that has a broader opening diameter at the lower end than that at the upper end is tried to be filled up with the thin film, there may occur a void in the depressed portion, or the impurities may be taken into the thin film.
U.S. Pat. No. 7,153,542, Japanese Patent No. 3144664 and U.S. Pat. No. 6,869,641 disclose apparatuses that deposit a thin film by the ALD method, but do not disclose measures to address the above mentioned concerns.